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Late model troubleshooting

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My Father-in-law has a late model sovereign 18, one of the command powered ones. seen here is the post from when we brought it home


Recently we have been having trouble starting it. The starter does not actuate when the key in turned to start. The seat switch has been bypassed, wire connected together. All the other safety switches are there.

The tractor will start and run properly, if the key is placed in the on position, and a wire is jumped from the battery positive to the blue wire on the solenoid above the starter body.  You can see this wire on the picture below. It is just below the main red battery cable.



I can’t tell from the diagram, so am I reading it right that late model Sovereigns have two separate solenoids?

Does this sound like one of the safety switches, interlock module or what?

Edited by GWGAllisfan
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Have you tried just jumping the two posts on the solenoid?  Is there any "clicking"?  Do you have power to the solenoid when the key is turned to the start position?  Sounds like it may be a bad solenoid.

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3 hours ago, GWGAllisfan said:

I can’t tell from the diagram, so am I reading it right that late model Sovereigns have two separate solenoids?

Yes, the Command powered Sovereign's have 2 solenoids, the "traditional" one behind the front dash panel and the second on the starter itself.  Al Eden stated the Command starter can be relatively easily damaged by low voltage, hence the main "+" 12v cable runs directly to the built in starter solenoid.  

The behind the dash solenoid sole function is to provide low amperage "start" voltage to the starter solenoid (blue wire after the engine harness connector).  BUT to get the dash solenoid to energize, the safeties must be satisfied.  This is accomplished by the "interlock module" providing a ground path from the dash solenoid,  The Command powered Sovereign wiring diagram:


The green hi-lighted wires show the +12v supply to BOTH sides of the dash solenoid (low amperage requirement for both).  The red hi-lighted wire shows the "start" wire to the starter mounted solenoid.  The blue hi-lighted wire shows the path to ground through all the safeties, including the interlock module.  

First thing I'd check is at the seat safety switch: with the hydro in neutral and the PTO disengaged, when you turn the ignition key to the "start" position, you should get +12v on the brown wire.  If you do, and the the bypass connection to the black wire is good (not corroded or broken wire) then the problem is at the interlock module or the wire to it.   

If not, the problem is further back the safety wiring path.  Next would be to see if there's voltage on the "upstream" side of the PTO safety switch (purple wire).  If you have voltage there, then the issue is that switch or the tan wire between the PTO safety switch and the seat safety switch.  If you don't have voltage, then check the trans safety switch.  

Good luck tracing the problem.

It's always good to check all ground connections, but I assume the engine shuts down when the ignition switch is turned to off, so the ground path from the ignition switch to interlock module to main ground at engine block base is OK (black wires).  


Edited by PhanDad
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